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JAM72S30-540/MR/1500V vs JAM78D30-585/MB/1500V 8 of 19 identical Swap Change panels

JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-585/MB/1500V

JAM72S30-540/MR/1500V
540 Wp 20.90 % PERC
Open panel page Datasheet PDF
VS
JAM78D30-585/MB/1500V
585 Wp 20.90 % PERC Bifacial
Open panel page Datasheet PDF
The verdict

JAM78D30-585/MB/1500V leads on the differences that matter

The largest is rated power: 45 W more power. 8 of 19 comparable parameters are identical.

See all 11 differences
How alike are they
8 of 19 comparable
parameters are identical
identical differs
01

What actually differs

11 of 19 parameters
Parameter JAM72S30-540/MR/1500V JAM78D30-585/MB/1500V Difference
Rated power 540 Wp 585 Wp 45 W more power
Performance warranty 25 yrs 30 yrs 5 yrs longer
Weight 27.3 kg 33.4 kg 6.1 kg lighter
Weight per kWp 50.6 kg/kWp 57.1 kg/kWp 6.5 kg/kWp lighter
Annual degradation 0.55 %/yr 0.45 %/yr 0.10 %/yr slower
Module area 2.583 m² 2.795 m² 0.212 m² apart
Open-circuit voltage 49.60 V 53.20 V 3.60 V apart
Cell count 144 156 12 cells apart
Bifacial No Yes No vs Yes
Voltage at max power 41.64 V 44.56 V 2.92 V apart
Dimensions 2278x1134x30 mm 2465x1134x35 mm 2278x1134x30 mm vs 2465x1134x35 mm
02

What it means on a roof

Thirty years of production
Each panel's own declared degradation curve, at 1,200 kWh/kWp a year
Same temp coeff. for both panels (-0.350 %/°C), so a warmer roof scales both curves by the same factor: the totals fall together and neither panel gains on the other.
JAM72S30-540/MR/1500V
17,501 kWh
JAM78D30-585/MB/1500V
19,265 kWh
Lifetime gap
1,764 kWh
Output when it is hot
Rated power carried across the range a module actually sees
Scenario JAM72S30-540/MR/1500V JAM78D30-585/MB/1500V
Standard test conditions 25 °C 100.0% of rated power 540 W 585 W
Cool, bright day 40 °C 94.8% of rated power 512 W 554 W
Typical summer roof 55 °C 89.5% of rated power 483 W 524 W
Hot roof 70 °C 84.2% of rated power 455 W 493 W
03

Full specification

Parameter JAM72S30-540/MR/1500V JAM78D30-585/MB/1500V Difference
Power and efficiency
Rated power 540 Wp 585 Wp +45 W for JAM78D30-585/MB/1500V
Module efficiency 20.90 % 20.90 % Same
Power density 209.0 Wp/m² 209.3 Wp/m² Effectively the same
Open-circuit voltage 49.60 V 53.20 V 3.60 V apart
Voltage at max power 41.64 V 44.56 V 2.92 V apart
Short-circuit current 13.86 A 13.88 A Effectively the same
Current at max power 12.97 A 13.13 A Effectively the same
Temperature
Temperature coefficient -0.350 %/°C -0.350 %/°C Same
Mechanical
Dimensions 2278x1134x30 mm 2465x1134x35 mm 2278x1134x30 mm vs 2465x1134x35 mm
Module area 2.583 m² 2.795 m² 0.212 m² apart
Weight 27.3 kg 33.4 kg -6.1 kg for JAM72S30-540/MR/1500V
Weight per kWp 50.6 kg/kWp 57.1 kg/kWp -6.5 kg/kWp for JAM72S30-540/MR/1500V
Warranty and degradation
Product warranty 12 yrs 12 yrs Same
Performance warranty 25 yrs 30 yrs +5 yrs for JAM78D30-585/MB/1500V
Annual degradation 0.55 %/yr 0.45 %/yr -0.10 %/yr for JAM78D30-585/MB/1500V
Technology
Cell technology PERC PERC Same
Cell type Monocrystalline Monocrystalline Same
Cell count 144 156 12 cells apart
Bifacial No Yes No vs Yes
04

Against the whole database

14,129 panels
Efficiency
#10,148 vs #10,148
Tied - the same position in the database
Power density
#10,176 vs #10,074
JAM78D30-585/MB/1500V leads by 102 places
Heat behaviour
#10,489 vs #10,489
Tied - the same position in the database
Weight
#3,965 vs #11,132
JAM72S30-540/MR/1500V leads by 7,167 places
Warranty
#9,912 vs #21
JAM78D30-585/MB/1500V leads by 9,891 places
Overall
#8,957 vs #6,198
JAM78D30-585/MB/1500V leads by 2,759 places
05

More useful comparisons

Open the full database
Same series, other bin
JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-605/MB/1500V
13 differences, the largest is module efficiency
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JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-600/MB/1500V
13 differences, the largest is rated power
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JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-595/MB/1500V
13 differences, the largest is rated power
Same series, other bin
JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-590/MB/1500V
12 differences, the largest is rated power
Same series, other bin
JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM78D30-580/MB/1500V
12 differences, the largest is rated power
Same series, other bin
JA Solar JAM72S30-540/MR/1500V vs JA Solar JAM72D30-580/LB/1500V
13 differences, the largest is module efficiency
06

Written summary

07

Questions about this pairing

Which panel is better: JA Solar JAM72S30-540/MR/1500V or JA Solar JAM78D30-585/MB/1500V?
According to our database: both panels are closely matched on key specs - the decision often comes down to price and local availability. See the full spec comparison and 30-year energy simulation above for a complete picture.
What is the efficiency of JA Solar JAM72S30-540/MR/1500V and JA Solar JAM78D30-585/MB/1500V?
JA Solar JAM72S30-540/MR/1500V has a module efficiency of 20.90%, while JA Solar JAM78D30-585/MB/1500V is 20.90%. Higher efficiency means more electricity from the same roof area - useful when space is limited.
What cell technology does JA Solar JAM72S30-540/MR/1500V use vs JA Solar JAM78D30-585/MB/1500V?
JA Solar JAM72S30-540/MR/1500V uses PERC cells; JA Solar JAM78D30-585/MB/1500V uses PERC. Modern n-type technologies (TOPCon, HJT, BC) typically deliver higher efficiency and lower degradation compared to older PERC (p-type) cells.
What is the warranty on JA Solar JAM72S30-540/MR/1500V and JA Solar JAM78D30-585/MB/1500V?
JA Solar JAM72S30-540/MR/1500V has a 25 years power warranty; JA Solar JAM78D30-585/MB/1500V has a 30 years power warranty. The power warranty guarantees a minimum percentage of rated output at the end of the warranty period (typically 80-87%). Product (materials) warranties are usually shorter.
Are JA Solar JAM72S30-540/MR/1500V and JA Solar JAM78D30-585/MB/1500V bifacial panels?
JA Solar JAM78D30-585/MB/1500V is bifacial (captures light from both faces); JA Solar JAM72S30-540/MR/1500V is monofacial. Bifacial panels work best on ground mounts or raised structures with a light-coloured surface underneath.

Shop prices: See 330 JA Solar offers

Every figure here is from the manufacturers' own datasheets - a dash means the value is not published, never an estimate. The thirty-year projection and the temperature scenarios are calculations from those figures, and each states its assumption above.